1. Field of the Invention
The present invention relates to an automatic ice maker, and more particularly to an automatic ice maker capable of saving an ice making time by using thermoacoustic refrigeration, and a refrigerator having the automatic ice maker.
2. Description of the Prior Art
Generally, a refrigerator is an apparatus for storing various foods in either a frozen or refrigerated condition to keep freshness of the foods for a long time. Such a refrigerator includes a compressor which circulates a refrigerant by compressing the refrigerant, a condenser for condensing the refrigerant to a liquid phase, and an evaporator for generating a chilled air by evaporating the liquid phase refrigerant.
The refrigerator has a freezing chamber for storing frozen foods such as meats or an ice cream, and a refrigerating chamber for storing foods at a relatively lower temperature. The chilled air generated by the evaporator is introduced into the refrigerating and freezing chambers by a fan.
An ice maker having an ice tray is installed in the freezing chamber for making an ice by using the low temperature of the freezing chamber. A water supply device feeds water into the ice tray and a driving device rotates the ice tray to separate the ice from the ice tray when an ice making process has been completed.
Examples of the ice maker are disclosed in U.S. Pat. No. 5,177,980 (issued to Akira Kawamoto, et al.) and U.S. Pat. No. 5,400,605 (issued to Sung-Ki Jeong).
FIG. 1 is a perspective view for showing a conventional automatic ice maker. As illustrated in FIG. 1, a driving section (not shown) is disposed at a front portion of a freezing chamber, and a fixing member 41 which is protruded rearward and has an L-shape is disposed at one end of the rear portion of the driving section. In the driving section, a driving apparatus having a motor, a gear mechanism and a rotating shaft 20 is installed. The driving apparatus reduces the rotation speed of the motor by the gear mechanism and transmits the reduced rotational speed to rotating shaft 20.
In fixing member 41, an ice tray 10 is disposed. At the front center portion of ice tray 10, a rotating pin 11 is formed. The front center portion of rotating pin 11 is connected to and supported by rotating shaft 20 which receives the rotational force generated by the motor. In addition, at the rear portion of ice tray 10, a supporting shaft 13 is formed. Ice tray 10 is rotatably fixed to fixing member 41 through supporting shaft 13. The rotational force generated by the motor is transmitted to rotating shaft 20 through the gear mechanism, and the rotational force is transmitted to ice tray 10 through rotating pin 11. Accordingly, ice tray 10 can be rotated by the rotation of rotating shaft 20.
Ice tray 10 is made of synthetic resin, such as plastic, which can be twisted laterally. Ice tray 10 has a hexahedral shape of which the upper surface is opened. The inside of ice tray 10 is partitioned into a plurality of concave portions to make the ice. The cross-section of the side portion of the concave portion has a reverse mesa shape for advantageously removing the ice from ice tray 10. Water is supplied into ice tray 10 by a water feeding apparatus.
At the rear portion of ice tray 10, that is, at one edge portion where supporting shaft 13 is formed, an ice separating plate 15 is formed along the length of ice tray 10. In addition, at one corner portion of fixing member 41, that is, at the corner portion opposite to ice separating plate 15, a stopper 31 is formed. Stopper 31 makes contact with ice separating plate 15 to limit the rotation of ice tray 10 when ice tray 10 is rotated to separate the ice from ice tray 10.
At the lower portion of the freezing chamber and below ice tray 10, an ice reservoir (not shown) is disposed. The separated ice through the rotation of ice tray 10 is stored in the ice reservoir.
FIG. 2 is a schematic perspective view for explaining the ice separating process in the conventional automatic ice maker.
In the conventional automatic ice maker illustrated in FIG. 1, when the ice is obtained in the concave portion of ice tray 10, a microcomputer (not shown) senses the ice through a temperature sensor (not shown) provided in ice tray 10. When the microcomputer determines that the ice is made in ice tray 10, the microcomputer sends an ice separating signal to the motor for driving the motor. The rotational force of the motor is transmitted to rotating pin 11 through rotating shaft 20 so that ice tray 10 rotates at an angle of 180 degrees, as illustrated in FIG. 2. At this time, ice separating plate 15 makes contact with stopper 31 for preventing a further rotation of ice tray 10. However, the rotational force of the motor is still transmitted to ice tray 10 through rotating pin 11. Accordingly, ice tray 10 is subjected to a torsional stress, so the ice formed in ice tray 10 is separated from ice tray 10 and falls down into the ice reservoir.
However, in the conventional automatic ice maker, the ice making is carried out by using the temperature of the freezing chamber, so a relatively long time is required for making the ice. If a user wants to rapidly make the ice, an energy loss results because the user should raise the temperature of the freezing chamber.
In order to overcome the above problem, a refrigerator having a separate ice making chamber in a freezing chamber is suggested. In the above refrigerator, a chilled air is guided into the ice making chamber through a duct so the ice making chamber has a relatively lower temperature than the temperature of the freezing chamber. However, this kind of refrigerator may reduce a usable space in the freezing chamber.